Isomerization processes, which rearrange the molecular form of a hydrocarbon feedstock while minimizing cracking reactions, are well known in the art. While lighter alkane hydrocarbons feedstocks are often subjected to isomerization steps, a most popular form of isomerization is for pentane and heavier hydrocarbons. Impetus for the isomerization of pentane comes from the need to improve the antiknock quality of the lighter portions of gasoline fuel blends. For example, n-pentane having a clear research octane rating of about 62 can be converted to isopentane have a clear research octane rating number of 92. Accordingly, refiners who maximize production of motor fuel will add isomerization steps to counteract restrictions on use of antiknock additives to improve the quality of blending refinery stocks that are suitable for premium grade motor fuels.
A process simulator is useful to refinery operators in a variety of ways. For example, a computer program which simulates current operation of the refinery, provides an important capability. Such a simulator can provide a wealth of information not readily available from control instrumentation. Further it provides this information in a easily understandable form for both the operator and the refinery engineer. Process simulators can be especially useful, for example in planning the catalyst replacement cycle, since the operator can evaluate the impact of replacing the catalyst with fresh, regenerated or a different catalyst at any desired time. He can then determine optimum replacement cycles and plan shut downs accordingly.
It is an object of this invention to develop a mathematical model for a commercial size isomerization unit.
A further object of this invention is to produce a computer program using a mathematical model for closely simulating the isomerization of pentane feedstocks so is to provide guidance to refiners for improving commercial operations.
A more specific object of this invention is to provide a reactor simulator for testing new operating conditions.
Another specific object of this invention is to evaluate at any time the impact of replacing the isomerization catalyst with fresh or a different catalyst.
A still further object of this invention is to provide a simulator for training operators.